Heat seals are used for a variety of applications for numerous industries. Typically, a polymeric material is heated to produce a seal between two portions of an article for a period of time until an appropriate seal is achieved. Unfortunately, the thermal process is timely. For instance, the process to seal a polymeric material includes heating the article and cooling the article to complete the cycle, which can take several minutes. This period of time is too lengthy on a manufacturing scale for efficient commercialization.
To reduce the sealing time, a dielectric welding technique is used. The dielectric welding technique, also known as high frequency or radiofrequency welding, uses both high frequency electromagnetic energy and pressure to create a seal. The dielectric welding technique takes a fraction of the time compared to thermal welding; however, dielectric welding can only be applied to particular polymers. Polyvinylchloride (PVC), functionalized polyolefins including ethylene copolymers or terpolymers of vinyl acetate or acrylic or methacrylic acids or esters or their derivatives, and thermoplastic polyurethane (TPU) are commonly used thermoplastic polymers conducive to dielectric welding. These particular polymers are conducive to dielectric welding due to their high dielectric loss factor (i.e. greater than 0.1) or dissipation factor tangent delta of the polymeric material. Unfortunately, these polymers may not have physical or mechanical properties desired for certain applications.
Polymers that may be desired typically include those that are flexible, transparent, and appropriate for certain applications. Unfortunately, many of these polymers can only be sealed thermally due to their inert nature, i.e. their low dissipation factor, and they cannot be sealed with dielectric energy. As a result, manufacturers are often left to choose the physical and mechanical properties they desire without an option as to whether it can be sealed quickly with dielectric energy.
As such, an improved polymeric material that can be sealed with dielectric welding is desired.